1. Field of the Invention
The present invention relates to a manufacturing method of a spacer used in an electron-beam apparatus such as an image-forming apparatus in which an electron beam is employed, and a manufacturing method of the electron-beam apparatus provided with the spacer.
2. Related Background Art
Heretofore, as an image-forming apparatus in which electron-emitting devices are utilized, an evacuated plane type electron-beam display panel is known in which an electron source substrate having a number of cold-cathode electron-emitting devices thereon and an anode substrate having a transparent electrode and a phosphor thereon are confronted in parallel. Such an image-forming apparatus, in which field emission type electron-emitting devices are used, is disclosed in, for example I. Brodie, xe2x80x9cAdvanced technology: flat cold-cathode CRTsxe2x80x9d, Information Display, 1/89, 17 (1989). Further, such an image-forming apparatus, in which surface conduction electron-emitting devices are used, disclosed in, for example, U.S. Pat. No. 5,066,883 and the like. A flat electron-beam display panel permits reduction in weight and the enlargement of a screen compared to a cathode-ray tube (CRT) display unit which is widely used at present, and can provide a higher luminance and a higher quality image than a flat display panel utilizing liquid crystals and other flat display panels such as a plasma display and an electroluminescent display. FIG. 5 shows a perspective view of a conventional flat electron-beam display panel which is partially cut out, as one example of the image-forming apparatus utilizing the electron-emitting devices. The configuration of the electron-beam display panel shown in FIG. 5 will be detailed here. In this drawing, reference numeral 1015 is a rear plate, numeral 1017 is a face plate and 1016 is a side wall, and these members constitute a vacuum envelope. Further, numeral 1011 is an electron source substrate and 1012 is an electron-emitting device. In this example, one phosphor is disposed to one electron-emitting device. Moreover, numeral 1013 (a scanning electrode) and 1014 (a signal electrode) are wiring electrodes, and they are each connected to the electron-emitting device 1012. Furthermore, numeral 1019 is a metal back and 1018 is a phosphor. Moreover, 1020 is a spacer, which holds the electron source substrate 1011 and the face plate 1017 at predetermined intervals and which is arranged in a vacuum envelope as a supporting member against atmospheric pressure. Besides, each junction of the face plate 1017, the side wall 1016, the rear plate 1015 and the spacer 1020 is sealed with a low melting point glass frit.
In order to form an image on this electron-beam display panel, a predetermined voltage is successively applied to the scanning electrode 1013 and the signal electrode 1014 arranged in a matrix state, whereby the predetermined electron-emitting device 1012 positioned at the intersection of the matrix is selectively driven, and the phosphor 1018 is irradiated with emitted electrons to obtain luminescent points at predetermined positions. Besides, for the purpose of obtaining the luminescent points of a higher luminance by accelerating the emitted electrons, a high voltage is applied to the metal back 1019 so as to become a positive potential to the electron-emitting device 1012. Here, the applied voltage is within about several hundred volts to about several ten kilo volts, depending on the performance of the phosphor 1018. Accordingly, the distance d between the electron source substrate 1011 and the face plate 1017 is usually set to about several hundred xcexcm to about several mm so that vacuum dielectric breakdown (i.e., discharge) may not occur by this applied voltage.
As the display area of this electron-beam display panel increases, the rear plate 1015 and the face plate 1017 need to be thickened to suppress the deformation of a plate substrate due to a difference between a vacuum in the vacuum envelope and an external atmospheric pressure. Thickening the plate substrate not only increases the weight of the display panel but also causes the distortion of the panel and the reduction of a viewable angle range when viewed from an oblique direction. Therefore, the spacer 1020 is disposed, whereby a required strength of both the plates 1015 and 1017 can be relieved, which permits reduction in weight, decrease in cost and the enlargement of the screen. In consequence, the advantage of the flat electron-beam display panel can sufficiently be exerted.
For a material which can be used for this spacer 1020, there are required (1) having a sufficient strength to atmospheric pressure (compressive strength), (2) having a heat resistance which can withstand heating steps in a manufacturing process and a high vacuum formation process, (3) matching to the substrate, the side wall and the like of the display panel in thermal expansion coefficients, (4) being a highly resistant member having insulating characteristics which can withstand the application of a high voltage, (5) a gas emission rate being low in order to maintain a high vacuum, and (6) being workable in a good dimension accuracy and being excellent in productivity. As such a material, a glass material is usually used.
However, the display panel of the image-forming apparatus described above has the following problems.
First, a part of electrons emitted from the vicinity of the spacer hit against the spacer, or ions produced by the function of the emitted electrons adhere to the spacer, whereby spacer charging might be caused. Further, the electrons which reach the face plate are partially reflected and scattered, and its part hit against the spacer, whereby the spacer charging might be caused.
An object of the present invention is to provide a method of manufacturing by a simple process at a low cost a spacer having a surface structure which can suppress surface charging.
Further, another object of the present invention is to provide an electron-beam apparatus such as an image-forming apparatus which has a sufficient display luminance and which realizes a low cost by the use of the spacer manufactured by the above method or the spacer having such a function.
That is, an aspect of the present invention is directed to a manufacturing method of a spacer for an electron-beam apparatus provided with an airtight container, and an electron source and the spacer arranged in the airtight container, and the manufacturing method comprises the step of heating and drawing a base material of the spacer, a desired rough state being formed on the surface of the base material in the heating and drawing step.
Another aspect of the present invention is directed to a manufacturing method of a spacer of an electron-beam apparatus provided with an airtight container, and an electron source and the spacer arranged in the airtight container, and the manufacturing method comprises the step of heating and drawing a base material of the spacer, a desired rough state and an electroconductive film are formed on the surface of the base material in the heating and drawing step.
Still another aspect of the present invention is directed to a manufacturing method of a spacer of an electronic-beam apparatus provided with an airtight container, and an electron source and the spacer arranged in the airtight container, and the manufacturing method comprises the step of heating and drawing a base material of the spacer having a rough state on its surface.
A further aspect of the present invention is directed to a manufacturing method of a spacer of an electronic-beam apparatus provided with an airtight container, and an electron source and the spacer arranged in the airtight container, and the manufacturing method comprises a step of forming a rough state on the surface of the base material of the spacer, and a step of heating and drawing the base material on which the rough state is formed.